Understanding Your Laboratory Test: What It Is, Why It Is Ordered, and How to Read Your Results

A laboratory test is a medical analysis performed on a sample of your blood, urine, or other body fluid or tissue. It measures specific substances, cells, or markers in your body to help your doctor evaluate how well your organs are functioning and check for signs of illness or infection.

The Baker's yeast antibody test, also known as ASCA (Anti-Saccharomyces cerevisiae antibody) IgA test, measures the level of IgA antibodies in your blood that target Baker's yeast (scientifically called Saccharomyces cerevisiae). Baker's yeast is commonly used in baking and brewing.

Your doctor may order this test to help diagnose a medical condition, monitor a disease you already have, see how well a treatment is working, or screen for health problems before symptoms appear. It can also be part of a routine checkup to establish baseline values for your overall health.

Your healthcare provider may order this test if you have symptoms of inflammatory bowel disease (IBD), such as abdominal pain, diarrhea, weight loss, or bloody stools. The test helps doctors distinguish between Crohn's disease and ulcerative colitis, two types of IBD that require different treatments.

Most lab tests require a small sample of blood drawn from a vein in your arm, though some tests use a urine, saliva, or swab sample instead. The collection usually takes only a few minutes and may cause brief, mild discomfort. Depending on the test, you may need to fast beforehand, and you can usually return to your normal activities right after the sample is collected.

A healthcare professional will draw a small blood sample from a vein in your arm. The sample is then sent to a laboratory for analysis. The procedure only takes a few minutes and is generally well-tolerated.

Your results are compared with a reference range, which is the range of values typically seen in healthy people. A result outside this range does not always mean you are sick, and normal results do not always rule out every condition. Your doctor will interpret your values together with your symptoms, medical history, and other tests, so be sure to ask what your specific results mean for you.

Results are usually reported as positive or negative. A positive result means that IgA antibodies against Baker's yeast were detected in your blood. This is found in approximately 50-80% of people with Crohn's disease. However, some healthy individuals may also have these antibodies, and some people with Crohn's disease may not have them. Your doctor will interpret your results along with other clinical findings and tests.